A. Field of the Invention
In general, the present invention is used for physical fitness and muscular development. The present invention is a training device for strengthening the arm, shoulder, and back muscles of athletes in sports utilizing player swung implements (i.e. rackets, bats, clubs, sticks, etc.). It utilizes aerodynamic drag principles to produce resistance against the motion of the stroke. The present invention is a light weight attachment to standard swung implements in the aforementioned sports. Although the physical dimensions of the present invention will vary based on the particular sports application, they utilize the same novel features to be enumerated in below. Presently on file with Patent and Trade Office is a Disclosure Document #264714, a copy of such enclosed, stating the date of invention as Mar. 23, 1990.
The ideal form of exercise is called "functional exercise" by Physical Therapists. Basically, functional exercise is exercise where specific muscle groups used by the stroking motion of a particular sport are taxed greater than normal. The opposing forces must be evenly distributed relative to the entire stroking motion (i.e. from the ready position to the backswing through to the follow-thru) and must not alter said motion. Numerous prior art utilize the principles of aerodynamic drag for exercise. However, each of these is missing one or more features that makes the present art unique.
B. Prior Art
The most common exercise of arm, shoulder, and back muscles include weight room training and weighted accessories to sports implements. Physical Therapists offer special exercises for rehabilitation of injured arms and shoulders usually involving coiled springs or elastic ropes. Also available are computerized iso-kinetic machines which offer variable resistance for a given force yielding a consistent speed. none of these replicate the actual stroking motion and are therefore not considered pure functional exercise.
The present invention was created from a desire to produce an exercise trainer for use at home during the off-season. The first sport addressed was tennis. Initially, a tennis racket was swung in a repetitive sequence with the "racket cover" on. The air resistance was noticed to provide significant drag. Next, cardboard models were designed with larger diameter "plane-like" surfaces. These were attached to the racket. The cardboard was lighter than the racket cover and the air resistance was greater. However, a large flat surface when stroked produced vibration in the implement's handle because the air slipped passed the outer edges unevenly. The racket stroke was misdirected by the unequal air pressure. Also, the large surface area, which was required to produce adequate resistance, became too cumbersome to manipulate.
The next model utilized a thin gauge plastic sheet. It was formed into a "pan-like" device which had a 16 inch diameter flat surface with a 3 inch high wall (or depth) around the perimeter. The wall provided the needed stability and eliminated the vibration in the handle. It trapped the air in front of the device during the stroking motion. This creates a greater air turbulence (or partial vacuum) behind the device increasing the drag. Ribs were added to strengthen the wall and to stiffen the body surface. The combination of the ribs and wall formed air pockets. The air pockets increased the resistance per unit of surface area because the air could not easily escape. Optimization of drag forces are achieved when the largest amount of air is captured and the greatest partial vacuum is generated per unit of surface area. Since most stroking motions form a large arc, it was found that a higher wall section along the most distant radial edge assisted in increasing drag.
The present art weighs less than 8 ounces due to the thin gauge material and maximized drag per unit surface area. Testing revealed that devices which add more than 8 ounces to the weight of the implement generated momentum forces that oppose (i.e. neutralize) the drag forces. The net effect of excessive momentum is to reduce drag. Also, gravitational forces created by excessive weight made the implement feel too heavy. Both the momentum and gravitational forces tended to distort the pure functional exercise. They caused an imbalance in the distribution of forces throughout the stroke.
In a few particular sports (i.e. golf and baseball), it was discovered that the shaft of the implement rotated along the its axis as much as 180 degrees while it was being swung. The rotation of the implement is typically caused by the wrists and hands working together to swing the implement. A device that is firmly locked to the implement will rotate along with the implement causing the angle of attack to become less than 90 degrees. The angle of attack should remain at 90 degrees throughout the entire stroking motion. The greatest resistance is achieved when a device remains perpendicular to the angle of attack during the stroke while the shaft of the implement rotates on its axis.
Therefore a device must provide for a means to rotate in the opposite direction of the shaft rotation. This counter rotation is accomplished by the present invention. The present invention balances the aerodynamic forces on both sides of the implement shaft during the backswing as well as the forward swing. The backside surface was so designed as to facilitate the balanced deflection of drag forces. The design features include rounded edges and angular ribs.
In addition, to facilitate the counter rotation, the present invention was developed to have a friction rotation attachment means. This means secured the implement to the device while at the same time allowed the device to rotate on the shaft of the implement as the drag forces dictated. Thus, the present invention remained perpendicular to the aerodynamic forces as the shaft of the implement rotated on its axis throughout the stroke. The above mentioned principles were successfully applied to numerous sports swung implements thus creating the present art.
Among the heretofore proposed devices or accessories of the character just described are those disclosed in U.S. Pat. Nos. 3,820,785 issued Jun. 28, 1974, to Occhipinti; 3,809,397 issued May 7, 1974, to Gruenewald; 4,603,854 issued Aug. 5, 1986, to Krausz; 4,183,526 issued Jan. 15, 1980, to Brown; 4,330,121 issued May 18, 1982, to McCafferty; 4,907,800 issued Mar. 13, 1990 to Passamaneck. Each of these patents is designed to generate aerodynamic drag and thereby promotes muscular development and coordination. The prior art uses principles of aerodynamics. However, none of the prior art accomplishes all of the following objectives:
(1) maximizes the drag forces per square unit surfaces area PA0 (2) provides stability and eliminates vibration while stroking PA0 (3) compensates for implement rotation during stroke by utilizing counter rotation attachment means PA0 (4) minimizes weight generated inertial and gravitational forces PA0 (5) an attachment means such that actual implements may be used PA0 (1) a large pan-like surface area or body in which the forward stroke captures the maximum amount of air and inturn creating a large vacuum or turbulence while maintaining its perpendicularity to the on rushing air. PA0 (2) the backside designed to deflects air evenly on the backswing. PA0 (3) a plurality of walls, ribs, and air pockets which enhance the co-efficient of drag. PA0 (4) optimization of drag forces while minimizing the negative forces of too much weight. PA0 (5) an attachment means.
The prior art with large flat plane-like designs tend to allow air to escape over the edges. This reduces drag and creates instability. The instability causes vibration and misdirection of the stroke. These designs have been proven to have the least co-efficient of drag resistance.
McCafferty and Gruenewald address the problem where some sports implements rotate along their axis during a stroke. McCafferty uses the concept he calls "aerodynamic neutrality". His invention, being spherical, maintains the same drag independent of its rotation by the implement. The nature of the sphere, however, does not optimize aerodynamic drag.
Gruenewald's vanes are 90 degrees apart along the shaft. As the implement rotates, the air hits the vanes at various angles and escapes. This reduces drag and the implement is deflected by the pressure imbalances. Most prior art do not account for implement rotation and therefore, tend to rotate such that the angle of attack is less than 90 degrees.
Research of the market place has disclosed one device that uses aerodynamic principles for the sport of tennis. A patent is pending as of this writing on his device called "Resist Air", by inventor Hohn Mueller. His invention is believed to be substantially different from the present invention. First, the "Resist Air" is not an implement attachment but a self-contained device with its own handle. Second, it is cumbersome to use. Imagine an extra large ping pong paddle. The molded handle is attached to 1/2 inch PVC tubing. The tubing loops in a 26 inch diameter circle and attaches to the handle. Stretched over the tubing is a dacron fabric which provides the flat surface area. Finally, the "Resist Air" creates an unstable swing. There is vibration in the handle. Both the backward and forward swinging motion is often misdirected because the air escapes around the edges.